首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   17377篇
  免费   254篇
  国内免费   26篇
教育   12449篇
科学研究   1717篇
各国文化   206篇
体育   1423篇
综合类   7篇
文化理论   157篇
信息传播   1698篇
  2021年   158篇
  2020年   241篇
  2019年   343篇
  2018年   457篇
  2017年   467篇
  2016年   442篇
  2015年   314篇
  2014年   405篇
  2013年   3324篇
  2012年   353篇
  2011年   400篇
  2010年   343篇
  2009年   307篇
  2008年   360篇
  2007年   322篇
  2006年   323篇
  2005年   290篇
  2004年   303篇
  2003年   294篇
  2002年   250篇
  2001年   507篇
  2000年   359篇
  1999年   314篇
  1998年   172篇
  1997年   213篇
  1996年   188篇
  1995年   179篇
  1994年   192篇
  1993年   163篇
  1992年   228篇
  1991年   250篇
  1990年   241篇
  1989年   251篇
  1988年   207篇
  1987年   197篇
  1986年   211篇
  1985年   259篇
  1984年   187篇
  1983年   187篇
  1982年   168篇
  1981年   160篇
  1980年   144篇
  1979年   222篇
  1978年   160篇
  1977年   161篇
  1976年   122篇
  1975年   141篇
  1974年   135篇
  1973年   133篇
  1971年   114篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
76.
77.
The American Hospital Association (AHA) Resource Center indexes journals for the Health Planning and Administration (HEALTH) database and Hospital Literature Index (HLI). These journals, designated special list health journals, are selected to provide access to a wide and balanced coverage of hospital and health care administration and health policy literature. This article provides background information on HEALTH and HLI and describes special list health journals in detail (including historical information, information sources, and broad subject divisions). It also discusses AHA policies relating to journal and article selection and current subject distribution of special list health journals.  相似文献   
78.
Efforts to represent knowledge effectively have been central to progress in various aspects of medical informatics. These efforts range from relatively simple "electronic textbooks" to fairly sophisticated knowledge-based systems, which function as well as, or even better than, human experts faced with similar problems. Knowledge bases have been developed in many fields, but the relatively limited domains and structured language of medicine, as well as the importance of information in the provision of good medical care, have made research in medical knowledge representation an area of intense activity. This paper reviews representative knowledge bases and knowledge-based systems in medicine: electronic textbooks such as PDQ and the Hepatitis Knowledge Base (HKB), rule-based systems such as MYCIN, causal models (e.g., CASNET), and hypothesis- or frame-based systems, exemplified by PIP and INTERNIST-1. The paper describes the relationships among divergent approaches and provides a sense of current and future trends. It examines problems in knowledge-based systems, particularly in knowledge representation and acquisition, and the responses to these challenges. The latter include the use of domain-independent software shells for constructing knowledge bases, the adaptation and use of previously existing knowledge bases, and multiple uses of the same knowledge base for different purposes.  相似文献   
79.
Serials, one of the more complicated areas of library technical endeavors, has lacked the benefit of standards for a long time. Even now, with standards beginning to be available, the majority of institutions are not working within standard serials formats. A survey to determine the use of serials standards in libraries was conducted in 1988 by the American Library Association, Resources and Technical Services Division, Serials Section, Committee to Study Serials Standards. In the spring of 1988 a survey was sent to a group encompassing the Association of Research Libraries members, CONSER participants, United States Newspaper Program participants, Microform Project libraries, and some vendors and librarians who attended the Committee meetings on a regular basis. The survey questionnaire assessed the current level of serials standards awareness of librarians and vendors. Topics included the type of serials systems used, standards relevant to serials control and union listing and whether or not they are implemented, types and levels of training staff received in the application of standards, benefits of the standards, and areas where standards are most needed.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号